7f06072420
It is OK under most cases, but if you happen to also use COM in your application, you will have heap corruptions.
125 lines
3.3 KiB
C++
125 lines
3.3 KiB
C++
// Copyright (c) 2015 GitHub, Inc.
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// Use of this source code is governed by the MIT license that can be
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// found in the LICENSE file.
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#ifndef ATOM_BROWSER_API_TRACKABLE_OBJECT_H_
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#define ATOM_BROWSER_API_TRACKABLE_OBJECT_H_
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#include <vector>
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#include "atom/browser/api/event_emitter.h"
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#include "atom/common/id_weak_map.h"
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#include "base/memory/scoped_ptr.h"
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namespace base {
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class SupportsUserData;
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}
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namespace mate {
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// Users should use TrackableObject instead.
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class TrackableObjectBase : public mate::EventEmitter {
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public:
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TrackableObjectBase();
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// The ID in weak map.
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int32_t weak_map_id() const { return weak_map_id_; }
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// Wrap TrackableObject into a class that SupportsUserData.
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void AttachAsUserData(base::SupportsUserData* wrapped);
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protected:
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~TrackableObjectBase() override;
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// mate::Wrappable:
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void AfterInit(v8::Isolate* isolate) override;
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// Get the weak_map_id from SupportsUserData.
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static int32_t GetIDFromWrappedClass(base::SupportsUserData* wrapped);
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// Register a callback that should be destroyed before JavaScript environment
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// gets destroyed.
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static void RegisterDestructionCallback(void (*callback)());
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int32_t weak_map_id_;
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base::SupportsUserData* wrapped_;
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private:
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DISALLOW_COPY_AND_ASSIGN(TrackableObjectBase);
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};
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// All instances of TrackableObject will be kept in a weak map and can be got
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// from its ID.
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template<typename T>
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class TrackableObject : public TrackableObjectBase {
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public:
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// Finds out the TrackableObject from its ID in weak map.
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static T* FromWeakMapID(v8::Isolate* isolate, int32_t id) {
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if (!weak_map_)
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return nullptr;
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v8::MaybeLocal<v8::Object> object = weak_map_->Get(isolate, id);
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if (object.IsEmpty())
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return nullptr;
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T* self = nullptr;
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mate::ConvertFromV8(isolate, object.ToLocalChecked(), &self);
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return self;
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}
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// Finds out the TrackableObject from the class it wraps.
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static T* FromWrappedClass(v8::Isolate* isolate,
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base::SupportsUserData* wrapped) {
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int32_t id = GetIDFromWrappedClass(wrapped);
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if (!id)
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return nullptr;
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return FromWeakMapID(isolate, id);
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}
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// Returns all objects in this class's weak map.
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static std::vector<v8::Local<v8::Object>> GetAll(v8::Isolate* isolate) {
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if (weak_map_)
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return weak_map_->Values(isolate);
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else
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return std::vector<v8::Local<v8::Object>>();
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}
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TrackableObject() {
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RegisterDestructionCallback(&TrackableObject<T>::ReleaseAllWeakReferences);
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}
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// Removes this instance from the weak map.
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void RemoveFromWeakMap() {
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if (weak_map_ && weak_map_->Has(weak_map_id()))
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weak_map_->Remove(weak_map_id());
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}
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protected:
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~TrackableObject() override {
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RemoveFromWeakMap();
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}
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void AfterInit(v8::Isolate* isolate) override {
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if (!weak_map_)
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weak_map_.reset(new atom::IDWeakMap);
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weak_map_id_ = weak_map_->Add(isolate, GetWrapper(isolate));
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TrackableObjectBase::AfterInit(isolate);
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}
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private:
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// Releases all weak references in weak map, called when app is terminating.
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static void ReleaseAllWeakReferences() {
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weak_map_.reset();
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}
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static scoped_ptr<atom::IDWeakMap> weak_map_;
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DISALLOW_COPY_AND_ASSIGN(TrackableObject);
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};
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template<typename T>
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scoped_ptr<atom::IDWeakMap> TrackableObject<T>::weak_map_;
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} // namespace mate
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#endif // ATOM_BROWSER_API_TRACKABLE_OBJECT_H_
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